The main things that causes total weight to fluctuate:

So when you weigh yourself and see no changes, if could be that fat might have gone down 1kg while muscles have gained 1kg (increased metabolism, your body shape change for better)!

How about water, poop? Do you think they affect weight? Yes they do - water about up to 2kg, poop about up to 500grams (eeeeeee!).

1. Glycogen and Water Storage: Rice is rich in carbohydrates, which are stored in the body as glycogen, primarily in the muscles and liver. Each gram of glycogen is stored with approximately 3-4 grams of water. So, a carb-heavy meal like a large portion of rice can lead to increased glycogen and water storage, temporarily boosting your weight.

2. Sodium Content: Some rice dishes, particularly those that are processed or seasoned, contain high levels of sodium. Sodium causes the body to retain water, leading to an immediate increase in weight due to water retention.

3. Digestive Weight: The physical weight of the rice itself adds to your weight until it is fully digested and excreted. This is purely the physical mass of the food and not indicative of fat gain.

4. Insulin Response: Consuming a lot of carbohydrates can cause a spike in insulin levels. Insulin, a hormone that helps regulate blood sugar levels, can also cause your kidneys to retain sodium, leading to water retention and a temporary increase in weight.

5. Bloating and Gas: High intake of certain carbohydrates can lead to bloating and gas, particularly for individuals with sensitivities to certain types of carbs. This can increase the feeling of fullness and apparent weight gain, but it is not related to fat accumulation.

6. Altered Bowel Movements: A sudden increase in rice consumption, especially if it’s a change from your regular diet, can alter your regular bowel movements, leading to temporary constipation or bloating.

7. Fluid Distribution Shifts: Eating a large meal can shift fluid distribution in the body temporarily. This is especially true for meals that are large in volume or high in carbohydrates.

8. Short-term Inflammation: Any significant dietary change, including a large increase in carbohydrate intake, can lead to short-term inflammation in the body, which is often accompanied by water retention.

9. Gut Microbiota Changes: Your gut microbiota can react to different types of food, including rice. A change in diet can lead to temporary changes in the gut flora, sometimes resulting in bloating and water retention.

10. Decreased Physical Activity: After a large meal, you might feel less inclined to be active. This decrease in physical activity, even for a short period, might contribute to a lesser degree of calorie burning, which could affect weight.

While these factors can contribute to a temporary increase in weight after eating a large amount of rice, they are generally short-lived and don't represent true fat gain. Weight can fluctuate daily based on numerous factors, including diet, hydration, physical activity, and hormonal changes.